Telegraph Sport assesses how the Premier League's title chasers have bolstered
their squads in what has been a hectic transfer market

Recruitment Alexis Sanchez (watch video below) will give much-needed pace and firepower, while Mathieu Debuchy is a good replacement for Bacary Sagna at right-back. Versatile teenager Calum Chambers looks expensive at £16 million, but should prove to be a shrewd investment. Wenger will hope that goalkeeper Wojciech Szczesny benefits from having some serious competition in David Ospina.

Departures Arsenal had long-anticipated Sagna's departure after the Frenchman refused several offers of a new contract, although the fact he chose to join Manchester City makes his loss harder to take. Lukasz Fabianski proved his value on the way to helping win last season's FA Cup, but wanted first-team football and will be a good signing for Swansea. Nicklas Bendtner left Arsenal this summer, not that anybody is too bothered.

What they still need to doArsène Wenger is still looking for an imposing defensive midfielder: his side were thrashed by Manchester City, Chelsea and Liverpool last season, and must be more competitive against their rivals this time around. The centre of defence is also an area that needs strengthening, particularly if Thomas Vermaelen completes his much-protracted move to Manchester United.

Recruitment Didier Drogba's return to Stamford Bridge may be one of the best stories of the summer, but the signings of Diego Costa, Cesc Fàbregas and Filipe Luis could prove more significant. Costa (watch video below) must succeed where so many big-money strikers have failed, while the signing of Fàbregas will make sure Chelsea carry a goal threat from central midfield. Luis provides options at the back.

Departures There is a feeling of a new era after Frank Lampard and Ashley Cole were both allowed to leave. While the influence of both men will be missed, the timing was probably right for all parties. Rival clubs are still scratching their heads at how Chelsea convinced Paris Saint-Germain to pay £50 million for David Luiz while Romelu Lukaku can put Costa under more pressure by restarting where he left off at Everton.

What they still need to do Mourinho's biggest challenge is to meet home-grown player rules. Clubs are only allowed 17 foreign players over the age of 21 and Mourinho currently has too many. He would like to sell striker Fernando Torres, after a dire season last year, but could be forced to make a decision on his stalwart goalkeeper Petr Cech if the Belgian youngster Thibaut Courtois starts the season as Chelsea's first-choice.

Recruitment No Premier League team has been so active as Liverpool, although one gag doing the rounds is Liverpool's scouting 'network' could not get beyond passport control at Southampton docks. Adam Lallana, Rickie Lambert and Dejan Lovren were excellent players at St Mary's, but moving to a club expected to compete for the title is a major step up.

Departures Only one stands out. Luis Suárez's sale to Barcelona is now spoken of as if it was inevitable, although it was hoped he might wish to experience Anfield on a major European night. Despite suggestions in Spain, Liverpool are adamant they received the full sale clause for Suarez of around £75 million, which has funded numerous purchases. Other high profile names such as Pepe Reina, Lucas, Fabio Borini are also expected to go.

What they still need to do Liverpool are still in need of full-backs and a new number seven to replace Luis Suarez. Loic Remy had possession of the shirt only to fall foul of a medical. Rodgers courted Wilfried Bony, only for the Ivorian's price (fee and wage) to prove prohibitive. It is inconceivable Rodgers will go into August with only Daniel Sturridge and Rickie Lambert as his forward options. Signing full-backs has also proven to be a problem area: Rodgers is stlil trying to make additions in this area before the end of the transfer window.

Recruitment It has been a low-key summer at the Etihad Stadium, with Fernando arriving from Porto to bolster the midfield and Bacary Sagna being snapped up on a free transfer from Arsenal to provide competition and cover in defence. Goalkeeper Willy Caballero (watch video below) has also been signed. A commanding centre-back has been the top priority and City appear to have won the race to sign Porto's French defender Eliaquim Mangala.

Departures City's squad has been pruned, with Joleon Lescott and Gareth Barry leaving on free transfers. Joe Hart's goalkeeping understudy, Costel Pantilimon, has moved to Sunderland and Jack Rodwell and Scott Sinclair are likely to leave, while James Milner's future remains uncertain. Yaya Toure has not left, though, despite his bizarre behaviour at the end of last season.

What they still need to do The key for City now is to wrap-up the deal for Mangala. But having identified holding midfield, right-back and central defence as priority areas this summer, the club has ticked every box and recruited well. Alvaro Negredo's foot and ankle injury may leave City short of firepower in the early weeks of the season, so it may be prudent to seek some attacking cover.

Recruitment Hiring Louis van Gaal as manager has been the major change, but almost £60 million has also been spent on left-back Luke Shaw and midfielder Ander Herrera (watch video below). United still want a centre-half and central midfielder, with Mats Hummels and Thomas Vermaelen on the radar. Daley Blind and Angel di Maria are also targets.

Departures United have been wounded by several high-profile departures and the retirement of Ryan Giggs. Rio Ferdinand, Nemanja Vidic and Patrice Evra have all moved on and their exits have left United without experienced figureheads at the back. Fringe players such as Bebe and Federico Macheda have also gone and United will also listen to offers for Anderson, Nani, Javier Hernandez and Shinji Kagawa.

What they still need to do United are prepared to operate with a smaller squad this season, of around 20 players, due to their lack of European commitments. But there is an urgent need for experience at centre-half and left-back. United's need to recruit in midfield has been intensified, however, by the foot injury which will sideline Michael Carrick for three months. The club continue to insist that vast sums are available for new signings, but with the season just two weeks away, there is a pressing need for both quality and quantity.